This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The "Multicenter AIDS Cohort Study" (MACS) is a large, long term study of the natural history of human immunodeficiency virus (HIV)/AIDS in men. In recent years, the HIV/AIDS epidemic in the United States has changed: highly active antiretroviral therapy (HAART) has led to fewer HIV-related complications and longer survival. However, some people develop side effects from HAART such as body shape changes, high cholesterol and triglycerides (fats in the blood), and/or high blood sugar/diabetes mellitus. It is not known if these side effects, or chronic HIV infection itself, will affect rates of heart disease.